Chester e



pending application 191,605,

- The present invention "mixture is '1 NITED STATES PATENT, OFFICE.

I cnns'ma. E. ANDREWS, or rrr'rsnunen, PENNSYLVANIA,

PENNSYLVANIA, a CORPORATION or DELAWARE.

COMPANY, 01 PITTSBURGH,

DIMETHYL-DITSOPROPYL-BENZIDIN AZO DYES AND PROCESS OF MAKING SAME No Drawing;

To all whom it may concern:

Be it known. that I, CHESTER E. A nnnwap a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented 1- methyl-Diisopropyl-Benzidin Azo Dyes and Processes of Making Same, of which the fol-i lowing is a specification. 1

relates to'dyes produced from dimethyl-diisopropyl-benzidin, by coupling with a suitable hydroxy aro matic body, ora derivative of such an aromatic body, and to the productionof suchdyes.

Dimethyl-diisopropyl benzidin may conveniently be prepare nitro-cymene in n alkaline solution, by means of powdered zinc to produce hydrazocymene, and then subjecting the latter 'to the benzidin reaction. Such a process and the product thereof are claimed in my cofiled September 15, 1917.

The process of the present invention is eiiected in a general way, the following series of steps: Dimethyliisopropyl-benzidin is first tetrazotized and the product then coupled with the hydroxy body in an alkaline solution, while maintained at atemperature of 10 C. or below. This last mentioned reaction is likely to be rather slow, requiring in some instances one day and in some instances longer or shorter periods of time, depending upon the relative de ree 0 activity of the hydroxy body employe tenfperature, purity and "other factors.

As a specific example of the process, the folpropy -henzidin are dissolved in about 300 arts of hot water containing 24 parts of hydrochloric acid (gravity 1.2) V then cooled to about 10 maintained at this temperature a C. While further quantity of 36 parts of hydrochloric acid (gravity 1.2) is added, and bout 14.4:parts of sodium nitrite, previously dissolved in a small amount of water is added. This produces the tetrazo derivative of dimethyl diisopropyl ben zidin, The tatrazo deriva- I Specification of Letters Patent.

mlxin is completed, which by reducing mono parts of dimethyl-dilsoand the Patented Sept. 2, 1919.

1917., Serial o. 191,606.

tive is added to about 32 parts of salicylic acid dissolved in 200 parts of water contai ing about 9.5 parts of causticsoda. The is effected while stirring an the mixture is ke t at a temperature of 10 C. or below. T e mixture is then stirred AssmNoa 'ro THE saLnEN d while while at this temperature, until the reaction v L' in this particular example should be completed in about one day. During this time about 12 parts of caustic soda in solution are slowly added.

. The stirring is then discontinued andthe liquid, while still maintained at about 10 C. is allowed to settle, and the dye, in solid form separates out in theform of a yellowish brown powder, insoluble in water Instead of salicylic acid referred to in the above example, various other hydroxy bodies can be employed, such as al ha-naphthol, beta-naphthol, resorcinol, enol, pyrogallol, or the derivatives 0 aromatic hydroxy bodies, particularly the sulfonic acid derivatives such as Sch'aefiers acid (betanaphthol fnono sulfon'icacid) gammawaci (2 8-amino-naphthol-6-sulfonic acid), R- acid (beta-naphthol-3:G-disulfonic acid), chromotropic acid (1:8-dioxy-naphthalene- 3:6-disulfonic acid), H-acid (1-8-aminonaphthol-3z6-disulfonic acid), K-acid (1:8- amino-naphtholl:6-disulfonic acid), RR- acid (2 :8 a'mi-no-naphthol 3 :6 disulfonic acid), Neville and VVinther-acid alpha i 'naphthol sulfonic acid 4:4), Schoel rofifs acid alpha naphthol-sulfonic acid-1: 8), G- acid (alpha naphthol-3z6-disulfonic acid), l-naphthol-S-sulfonic acic.

With most of the simple hydroxy bodies, the sodium salt produced constituting the dye, is insoluble, whereas with the sulfonic acid compounds the sodium salt constituting the dye is in most cases solu le. Those (1 yes which are soluble, produced in accordance with this invention, can readily be separated from the solution of salting out.

In the present invention instead of using a single hydroxy aromatic bodg, be employe by the customary metho a mixture of such bodies can or prefercoon r some circumstances (two molecules of hydrochloric acid being formed the union of hydrogen"-andi chlori'n.

The following reaction is given as showing ubsequently another I "cli nt;

' cylic acid and beforesmentioned the other end of t e reactions taking place i of the present invention, *cylic acid' as the specific -e illustrated conveniently ascompounds e structure.

xamp follows coon m m-q. Example of tetralzotized' dimethyl' diiso propyl ben'zidin coupled at. at the other with ch is thylamin whi coupled n the process 10 employing 'saliw le may be i ll I one end with salialpha naphdiazoti-zed and coupled with Neyillea-nd Winthers acid. 25

i a P "1 [three molecules ofhydrochloric acid. being Thehereinadescribednew dyestufi's'con- Formed) v I 7 sistin' 'gfof'tetrazo dimethyl-diisopropyl-ben- 35 What is claimed isi; rzidinmcoupled'wit'h two hydroxy 'aromatic 1. The herein described new dyestu-ifs 0on bodies, at least one of which contains the istingof the tetrazo-compound'of dimethyL' naphthalene nucleus. 4 usopropyl-benzidin coupled with ah'ydroxy ln-testimony whereofl aflix mysignature; I romatic compound, said dyes being capable Y f-dyeing' fabric in an acidbath;

CHESTER E." ANDREWS. i

at- 'o 

